<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
     <div id='box'>点我啊</div>
    <script>

        var box=document.getElementById('box');
        var obj={
            n:1
        }
       function fn(){
           console.log(this);
       }

       box.onclick=fn.bind(obj);
       
    </script>
</body>
</html>